ORIGINAL ARTICLE Comparison of different criteria for periodontitis case definition in head and neck cancer individuals Audrey Cristina Bueno & Raquel Conceição Ferreira & Luis Otávio Miranda Cota & Guilherme Carvalho Silva & Cláudia Silami Magalhães & Allyson Nogueira Moreira Received: 16 August 2014 /Accepted: 13 January 2015 /Published online: 25 January 2015 # Springer-Verlag Berlin Heidelberg 2015 Abstract Purpose Different periodontitis case definitions have been used in clinical research and epidemiology. The aim of this study was to determine more accurate criterion for the defini- tion of mild and moderate periodontitis case to be applied to head and neck cancer individuals before radiotherapy. Methods The frequency of periodontitis in a sample of 84 individuals was determined according to different diagnostic criteria: (1) Lopez et al. (2002);(2) Hujoel et al. (2006); (3) Beck et al. (1990); (4) Machtei et al. (1992); (5) Tonetti and Claffey (2005); (6) and Page and Eke (2007). All diagnosis were based on the clinical parameters obtained by a single calibrated examiner (Kw=0.71). The individuals were evalu- ated before radiotherapy. They received oral hygiene instruc- tions, and the cases diagnosed with periodontitis (Page and Eke 2007) were treated. The gold standard was the definition 6, and the others were compared by means of agreement, sensitivity (SS), specificity (SP), and the area under ROC curve. The kappa test evaluated the agreement between definitions. Results The frequency of periodontitis at baseline was 53.6 % (definition 1), 81.0 % (definition 2), 40.5 % (definition 3), 26.2 % (definition 4), 13.1 % (definition 5), and 70.2 % (def- inition 6). The kappa test showed a moderate agreement be- tween definitions 6 and 2 (59.0 %) and definitions 6 and 1 (56.0 %). The criterion with higher SS (0.92) and SP (0.73) was definition 1. Conclusion Definition 1 was the most accurate criterion to case periodontitis definition to be applied to head and neck cancer individuals. Keywords Diagnostic criteria . Periodontitis . Epidemiology . Periodontitis/definition Introduction Periodontitis is a chronic inflammatory disease caused by an infection of the supporting tissues around the teeth. The infec- tion begins with the colonization and growth of small groups of Gram-negative bacteria and spirochetes such as Porphyromonas gingivalis, Tannerella forsythia, and Trepo- nema denticola. These bacteria, among others, are part of the biofilm, which apically extends along the roots of the teeth, leading to the formation of the periodontal pocket and destruc- tion of the alveolar bone and periodontal fibers [1]. The point at which periodontitis can be diagnosed is called the diagnostic threshold. Ideally, the diagnosis should be ac- curate, consistent, of easy execution, and should occur in the initial stage of the disease [2]. Generally, the clinical diagnosis of periodontitis is based on the measurement of the probing depth (PD), clinical attachment loss (CAL), bleeding on prob- ing (BOP), and loss of the alveolar bone, with or without the use of radiographic exams [1–3]. There is no uniformity in the criteria for defining and mea- suring periodontitis and its extent and severity [1, 2, 4–8]. A. C. Bueno (*) : G. C. Silva : C. S. Magalhães : A. N. Moreira Department of Restorative Dentistry, School of Dentistry, Federal University of Minas Gerais, Avenue Antônio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, Minas Gerais, Brazil e-mail: audreybueno@ig.com.br R. C. Ferreira Department of Social and Preventive Dentistry, School of Dentistry, Federal University of Minas Gerais, Avenue Antônio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, Minas Gerais, Brazil L. O. M. Cota Department of Periodontology, School of Dentistry, Federal University of Minas Gerais, Avenue Antônio Carlos 6627, Pampulha, 31270-901 Belo Horizonte, Minas Gerais, Brazil Support Care Cancer (2015) 23:2599–2604 DOI 10.1007/s00520-015-2618-8